너의 시간 속으로

For the non-spoiler part:

1. The time travel is straightforward and easy to follow. No advance time travel theories. No time travel gymnastics. Nothing crazy. Pretty much linear.

I strongly advise finishing the entire series first because the show itself explained the linearity of the time travel. Again, it's simple and easy to follow.

However… this is the SPOILER part.

They made a mistake on two things:

1. They dated the murder of Kwon Min-Ju on 1998-10-13.
2. When Han Jun Hee arrived in July 1998, her dialogue was she realised she only had 3 months to save Min-Ju.

Yet, in Episode 10/11, when Jung In-Kyu was about to jump to his death, he recalled the Christmas he, Nam Si-Heon, and Kwon Min-Ju, spent together. If Kwon Min-Ju did die on 1998-10-13, then how did he have a memory of spending Christmas together?

Kwon Min-Ju was murdered on 1999-10-13. Han Jun-Hee controlled the body of Kwon Min-Ju for almost 15 months. She spent 5 months in 1998; and spent 10 months in 1999. Not 3 months in 1998.

I'm not sure how they missed this very important detail; or why they filmed a Christmas scene and included it in Jung In Kyu's memories. If Kwon Min-Ju was indeed murdered in 1998-10-13, then the Christmas scene was not possible. If the Christmas scene was correct, then she died on 1999-10-13.